The present invention relates to computer telephony systems. More particularly, the invention relates to deferring background processing to improve the quality of computer telephony audio.
Computers continue to permeate technology areas because they can offer significant advantages in terms of convenience and flexibility over non-computer technologies. Telephony systems are an example where computers are increasingly being utilized to add features and lower costs.
Although computer telephony can provide users with greater convenience and flexibility, conventional computer telephony have problems related to what has become known as “choppy audio.” Choppy audio refers to the variable and abnormal delay of segments of sound delivered to the user. These delays can result in annoying gaps in the audio heard by the listener as opposed to the more natural continuous sound that is heard on conventional telephones over circuit-switched networks.
One cause of choppy audio is packet loss. Packet loss is typically caused by highly overloaded processors and network links and by error prone links. These causes should abate in importance as faster processors and higher bandwidth links are installed and as noise-prone analog links are replaced by digital links.
Network delays are another cause of choppy audio. In recent years, a jitter buffer has been used to mask the impacts of network delays on sound quality. A jitter buffer buffers the sound by inserting delays to impose a consistent network delay, as opposed to the unpredictable delays caused by the network in the absence of this jitter buffer. Many users find that a consistent delay is preferable to choppy audio.
Another cause of choppy audio is misbehavior of video cards. Striving for the best benchmarks for video cards, video card manufacturers often design the video cards to monopolize the bus (e.g., PCI bus) so that there is not enough of this resource available for audio use to prevent choppy audio. A less aggressive video card can significantly decrease this cause.
Although the previously described solutions to choppy audio can be utilized alone or together to reduce choppy audio, choppy audio can still be caused by client processing delays. Many computer telephony clients are based on general purpose platforms such as Windows-based and Unix-based workstations that are used for multiple applications. There is now a large and rapidly growing number of applications on these platforms that run potentially resource-intensive programs in the background (i.e., not under the immediate interactive control of the computer user). Examples of background processes include virus checking processes, word processing processes that save recent changes, email processes that check for mail, processes that backup data, and the like.
When background processes execute on a client workstation during a computer telephony call, choppy audio may result and the results can be particularly severe when several of these background processes are running at the same time. It would be beneficial to have techniques for reducing choppy audio caused by client processing delays in computer telephony systems.